
63
Fault code
on the dis-
play
System characteris-
tics
Cause
Measures
9A
Control mode
Lead break, collec-
tor temperature
sensor; connects
to the Vitosolic at
S1
Check the sensor at the
Vitosolic.
9b
Control mode
Lead break, cylin-
der temperature
sensor; connects
to the Vitosolic at
S3
Check the sensor at the
Vitosolic.
9C
Control mode
Lead break, tem-
perature sensor;
connects to the
Vitosolic at S2
Check the sensor at the
Vitosolic.
9F
Control mode
Solar control unit
fault; displayed if a
fault without fault
code occurs at the
solar control unit
Check the solar control
unit (see solar control unit
service instructions).
A7
Control mode as per
delivered condition
Faulty program-
ming unit
Replace the programming
unit.
b0
Burner blocked
Short circuit, flue
gas temperature
sensor
Check the flue gas tem-
perature sensor (see
page 70).
b1
Control mode as per
delivered condition
Communication
fault, programming
unit (internal)
Check connections and
replace the programming
unit if required.
b4
Controls as if the out-
side temperature
were 0 °C
Internal fault
Replace the control unit.
b5
Control mode as per
delivered condition
Internal fault
Replace the control unit.
b7
Burner blocked
Boiler coding card
missing, faulty or
incorrect boiler
coding card
Plug in boiler coding card
or replace it, if faulty.
b8
Burner blocked
Lead break, flue
gas temperature
sensor
Check the flue gas tem-
perature sensor (see
page 70).
Troubleshooting
Fault codes
(cont.)
5692 774 GB